ROME, March 20 (Thomson Reuters Foundation) - Rising protectionist and anti-trade sentiments threaten efforts to curb malnutrition even as more people go hungry and climate pressures rise, a U.S.-based think-tank said on Tuesday.

The International Food Policy Research Institute (IFPRI) noted the benefits of a free flow of goods - it improves the availability of food and keeps supplies stable, which prevents droughts from becoming famines.

It also helps nutrition by ensuring food variety.

"A longer-term issue is that everyone ends up poorer if you don't allow trade," said Will Martin, a senior research fellow at IFPRI and co-author of its annual Global Food Policy report.

Global hunger rose to 815 million people in 2016 from 777 million in 2015, according to the United Nations. Eliminating hunger and malnutrition by 2030 are part of the Sustainable Development Goals (SDGs), a global plan of action.

And last year the World Health Organization said 155 million children under five were affected by stunting, which hinders their growth and economic potential.

Martin said limiting trade would result in high prices in land-scarce countries, depressed food prices in countries with plenty of land, and lower incomes in both.

"It is totally a lose-lose situation," he told the Thomson Reuters Foundation by phone, noting that incidences of famine had reduced in India after railways expanded in the late 19th century, facilitating national trade.

The IFPRI said the political and economic uncertainties of recent years, such as the U.S. withdrawal in 2017 from the Paris accord to combat climate change, and Britain's decision to leave the European Union in 2016, would likely continue.

Hunger fueled by conflict - and made worse by drought - would add to the challenges of feeding people, as would climate change, the report said.

"This report is absolutely correct: robust, well-functioning global food markets are our best hope for meeting the needs of a growing, increasingly urban world," said Cullen Hendrix, a food security specialist at the University of Denver.

Critics of trade say it increases inequality, damages the environment and leads to unhealthy diets. Rather than trade barriers, the IFPRI said, safety nets, better management of resources and policies to tackle unhealthy foods would help.

Kim Elliott, from the U.S.-based Center for Global Development, acknowledged in an email interview that not all trade agreements were positive for developing countries.

However, increasing protectionist tendencies in the U.S. and elsewhere "undermine support for multilateral forums, such as the World Trade Organization, where developing countries can increase their bargaining power by banding together", she said. (Reporting By Thin Lei Win @thinink, Editing by Robert Carmichael. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, corruption and climate change. Visit www.trust.org)

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